The subject matter disclosed herein relates to chemical and biological sensors, and more particularly, to chemical and biological sensors capable of multivariate resonance enhanced impedance measurements.
Chemical and biological sensors are often employed in a number of applications where the detection of various fluids may be used to discern useful information. For instance, measuring the presence of vapors by discerning a change in certain environmental variables within or surrounding a sensor may be particularly useful in monitoring changes in biopharmaceutical products, food or beverages, monitoring industrial areas for chemical or physical hazards, as well as in security applications such as residential home monitoring, homeland security in airports, in different environmental and clinical settings and other public venues wherein detection of certain harmful and/or toxic vapors may be particularly useful.
One technique for sensing such environmental changes is by employing a sensor, such as a radio frequency identification (RFID) sensor, coated with a particular sensing material. Also, sensors may be arranged in an array of individual transducers which are coated with sensing materials. Many sensor arrays include a number of identical sensors. However, while using identical sensors simplifies fabrication of the sensor array, such an array may have limited capabilities for sensing only a single response (e.g. resistance, current, capacitance, work function, mass, optical thickness, light intensity, etc). In such applications, it may be beneficial to include an array of sensors wherein different transducers in the array employ the same or different responses (e.g. resistance, current, capacitance, work function, mass, optical thickness, light intensity, etc.) and are coated with different sensing materials such that more than one property can be measured. Disadvantageously, fabricating a sensor array having individual sensors uniquely fabricated to sense a particular response complicates fabrication of the array.
Further, in practical applications, it is beneficial to use highly selective chemical and biological sensors. That is, it is often desirable to provide a sensor array capable of sensing multiple vapors and vapor mixtures in the presence of other vapors and mixtures. The greater the number of vapors and vapor mixtures that may be present, the more difficult it may be to accurately sense and discern a specific type of vapor or vapor mixture being sensed. This may be particularly true when one or more vapors are present at levels of magnitude greater than the other vapors of interest for detection. For instance, high humidity environments often interfere with the ability of traditional sensors to detect selected vapors.
Therefore, it is beneficial to have a method in which environmental changes such as position changes, noise changes, temperature change, and repositioning changes are accounted for in a multivariate resonance enhanced impedance measurement.
Various embodiments disclosed herein may address one or more of the challenges set forth above.